Facsimile switching system



Jan. 9, 1951 R. J. WISE Er A1.

FACSIMILE swITcHING SYSTEM 9 Sheets-Sheet 1 Filed May 18, 1948 INVENTRS R. J. WISE M.J. REYNOLDS WTA@ AT ToR EY Jan. 9, 1951 R. J. WISE m- AL FACSIMILE swITcHING SYSTEM Filed May 18, 1948 INVENTORS R. J. WIS E BY M.J. REYNOLDS m *AL A TO NEY Jan. 9, 1951 R. v.1. wlsE Er AL 2,537,199

` FACSIMILE SWITCHING SYSTEM Filed May 18, 1948` v 9 Sheets-Sheet 5 DET INVERTOR Jan. 9, 1951. R. J. wlsE In' A1.

FACSIMILE SWITCHING SYSTEM Filed May 18, 1948 I I I I I I I I I I I l I I I I I I I l I I l I IOS lOl

NO DRUM il,

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INVENTORS R. J. WISE M.J. REYNOLDS BY To STORAGE JACKs |N OTHER PoslTloNs To TRUNK JAoKs T POS. 2

ATT RNEY IN OTHER POSITIONS -TO FIG. II-

Jan. 9, 1951 R. J. WISE r-:r Al. 2,537,199

FACSIMILE SWITCHING SYSTEM Filed May 18, 1948 9 Sheets-Sheet 5 je 6| 8 |65 |66 l67\ .63T -f-WO- MONITOR |64/ l 1mg M RECORDER 5 l {TL} I l 147 'M' i W a |56 AMP. g l

. I l "'QZT um; 13o T51: 12| I Yt; I

.12e |39 132x i w 1 maJ ?J 40 1w' i |480- E l laag H|a5bl l L T- I |300 laob 130C f g INVENTORS ATTOR 'EY Jan. 9, 1951 2,537,199

R. J. WISE El' AL FACSIMILE SWITCHING SYSTEM 9 Sheets-Sheet 7 Filed Mayl8, 1948 FIG. Il

STORAGE MESSAGE WAITING MESSAGE COMPLETED INVENTORS R. J. WISE BY M.J. REYNOLDS ATTO NEY Jan. 9, 1951 R. J. wlsE ET Al.

FACSIMILE SWITCHING SYSTEM '9 sheets-sheet 8 Filed May 18, 1948 (www v/ avm INVENToRs RJ. wlsE MJ. REYNOLDS ATT RN EY Jan. 9, 1951 R. J. wlsE ET AL FACSIMILE SWITCHING SYSTEM 9 Sheets-Sheet 9 Filed May 148, 1948 S I @IIC n v D mo mohm mwwokm U. .w S L R O dz. u w E N @I ..50 N Y zn. as n M W M m w w IF/ whum R M @lc [1| .560.4 m lllllllll I ICJ 111| uw@ I n r IIIIII .w I @mm WT I I am 5m W Ww L m5; m L Cm. .I F. hmm/NIH w I I l w I Nm ,Em I I i. h mwN mm1 H vo. m. I me m I m M. I m I I I I I I I l I I IIN. I I I I I I I I I I I I l I l I I III- r IIIIIIIII IIL I mv Il m. mi W .Il .C Img A 1 @wm d N: .T mwN ATTO N EY Patented Jan. 9, 1951 UNITED f." OFFC FACSIMXLE SWITCHENG SYSTEM Application May 18, 194:8, Serial No. 27,728

30 Claims. l This invention relates to a facsimile switching system and more particularly to such a system arranged to be operated in accordance with switching code signals accompanying or forming a part of the facsimile transmission. One of the objects of this invention is to provide a coded message blank to the switching code may be conveniently applied and from which the code signals may be transmitted by usual facsimilescanning means. Another object is to provide suitable switch ing code detecting means responsive to the transmitted signals for determining the required switching operation.

Still another object is Vto provide means for transmitting the switching signals from the message sheet and for subsequently and automatically transmitting the message, picture or other lac simile subject matter under the control or the switching operation.

A still further object is to provide means for` translating .facsimile signals into. telegraph code selecting impulses.

A further object is to provide` a facsimile switching system having means for automatically numbering switched messages.

Still another object is to provide suitable storagemechanism for received facsimile messages.

Another object is to provide a facsimile switchn ing system embodying intermediate storage and retransmission of facsimile subject matter.

Many other. objects and advantages will appear as the description proceeds.

In accordance with our invention we provide a facsimile message blank having a predetermined zone thereon in which a code address may, be readily inserted for transmission ahead of the body of the message by the usual facsimile scanning means. This code address initiates a call to the central switching oflice and operates suitable code detecting apparatus for visually india.` eating to the switchboard operator, the code designation of the station of destination of the mes sage awaiting transmission At the switching oiiice the operator may manually switch the incoming call to the desired local;A reco-rder, to an outgoing circuit or to local storage means for subsequent retransmission.

The facsimile transmitter is so controlled that only the coded switching information is initially transmitted under the control of the transmitting operator. This is eiecte-d by transverse scanning of the ycoded zone of the blank without longitudinal scanning of the messa The longitudinal scanning is under the controlei the Switchingofliceand is initiated by control signais transmitted from the switching oilice automatically upon the completion of the switching connection.

in the embodiments described hereinafter the switching is completed manually through jack and plug connections but is susceptible to operation by means of full automatic switchingequipnient.

In the case of a local message or a message designated for the central oiiice, the calling cirt is switched directly to a local recorder and, ii' destined :tor a remote station, the incoming circuit is switched to a trunk circuit which terminates in a recorder. In case Such local recorders or trunk circuits are busy, the incoming lines may be switched to an appropriate storage device for later transmission. As soon as a switching connection is made, the control of the calling transmit r is transferred to the called recorder or e device `which operates upon completion J,'.ansmission of a message to send a control signal to the station of origin of the message stop the transmitter and in addition to signal le operator at the switchboard position of the completion of the transmission so that she may unplug the connection.

When switching connection is made to a trunl: circuit, either directly from the calling lline or from a storage device, consecutive numbers in the form of facsimile signals are automatically inserted ahead of or interspersed with the message signals to provide the require-d lost message checking information at the recording station.

Gne such numbering machine is provided for each Y outgoing trunk.

The 'invention will be more fully understood by reference to the accompanying drawings, in which: i

Fig. l illustrates a ormcf coded message blank usable in carrying out the present invention;

Fig. 2 is asehematic showing one form ci' general circuit layout utilizing the invention;

3 shows the arrangements of the Sheets 2 7 of the drawings to form a composite circuit;

/i is a circuit diagram showing the facsimile transmitting equipment at a subscribers 0ffic-e or sub-station;

5 shows the jack switching arrangement a central station for extending calls from the trans; "ter of Fig. e to any desired destination, and includa@ the switching code detecting means associated with incoming circuits;

S is a iront View ci thel'code indicating panel arranged above the switchboard position;

Fig. 7 is a circuit diagram ofthe -facsimile realaaf/,19o

3 cording equipment at a local receiving position at the switching office;

Fig. 8 shows diagrai'nmatically an automatic means for numbering or identifying facsimile messages switched over an outgoing circuit;

Fig. 9 is a circuit diagram of the facsimile reicording mechanism and control means at the distant end of the outgoing circuit;

Fig. 10 is a, fragmentary showing of a message number transmitting form usable in the apparatus of Fig. 8;

Fig. 11 shows diagrammatically a form of facsimile storage apparatus and the associated retransmitting cord circuit; and

Figs. 12 and 13, together, show a system for extending calls through several manual switching centers, from the transmitting station to the station of destination.

Referring first to Fig. 1, the transmitting message blank lil there shown is of the usual telegraph blank form with the addition thereto of a zone H in which the switching address of the message may be indicated. This zone comprises a continuous dark portion i2, and a continuous light portion I3, the latter having a series of eight equally spaced index points i4, disposed therealong. In use it is contemplated that each ofce of destination associated with the switching system will have an individual code number of one or more digits formed by the digits 1 to 8 in ascending sequential order, as 134. The subscriber or sub-station operator on determining the number of the ofce of destination of a message places marks or lines transversely across `the code zone opposite the appropriate indexes.

The blank of Fig. l has been so marked for the code address 346.

Adjacent the bottom of the message blank is a series of dashes i equally spaced and of such length as to generate an alternating current of definite frequency when scanned by the transmitting scanning apparatus, as for instance, 70 cycles. This serves as an end-of-message signal.

The body or text of the message is written or typed in the space between the code zone Il and the end-of-niessage markings l5.

Referring now to Fig. 2, the system shown for using the coded message blank l) comprises a number of subscrbers offices or sub-stations, A1, A2, etc., each including a facsimile transmitter of suitable type for operation over an individual circuit comprising a pair of conductors L1, L2, terminating at a central office B in the receiving jacks RJi, RJz, etc. Associated with the line side of each receiving jack is an individual amplifier i6, the output side of which is connected to a common detector Il for converting the code signals transmitted from the blank i0 into D. C. signals for the operation of a code detector and visual indicator I8 from which the central office operator may determine the destination of the incoming message and make the appropriate switching connection.

Transmitting jacks are also arranged at the the start of each transmission over the lines TLI, TL2 for the purpose of applying consecutive number signals to each message transmitted thereover. Jacks TJ3 and TJ I3 are similarly connected to a second trunk circuit TLB, TL4, having a numbering machine 23 associated therewith and terminating in a facsimile recorder 22. Jacks TJ 4 and TJ I4 are shown connected to the receiving side of a suitable facsimile signal storage device 24 of the magnetic tape recording type, the transmitting side of which is provided with a plug 25 and associated cord circuit whereby messages stored therein may be subsequently switched to the appropriate destination. Connections between the incoming jacks RJ and outgoing jacks TJ are made by patching cords 25.

It will be understood, of course, that any desired number of receiving and transmitting positions may be provided and that the number of local jacks, trunk jacks and storage jacks, and their associated equipment which may be provided, is limited only by the limitations of the switching code. The eight-unit code shown provides a, maximum of 256 selections. It is to be further understood, however, that the eight-unit code is shown only by way of example and if desired any other desired number of code impulses may be employed. Since, as will appear hereinafter, these code pulses are transmitted as a modulated carrier, the pulsing frequency is not limited to usual D. C. line signaling frequencies, the limiting factor being the ability of the code detecting relays, to be described, to receive the signals. The code may, therefore, be expanded to permit thousands of selections if desired. However, if the code is expanded beyond nine units, it is preferable to employ alphabetical code designations.

Sub-station transmitter In describing the detailed circuit arrangements and associated equipment, the subscribers or sub-station facsimile transmitting equipment shown in Fig. 4 will be considered first. It is to be understood that this may comprise any suitable type of facsimile transmitter adapted to be controlled over the outgoing circuit, from the remote end, such as the slot machine type of transmitter shown in Patent 2,262,715 to Wise et al., or a vertical type of transmitter, such as shown in Wise et al. application Serial No. 454,768, led August 14, 1942, now Patent No. 2,469,423. For the purpose of illustration we have selected the latter type of transmitter. Briefly, this transmitter, Fig. 4, comprises a vertical transparent cylinder 2l mounted for rotation through a shaft 28 driven by a motor 29 through associated gearing 33. The cylinder 2 is adapted to hold, on the inside thereof, the rolled transmitting message sheet I and to scan the same through the wall of the transparent cylinder by an optical system comprising a light source 3|, a photocell 32, and an interposed toothed chopper disc 33 driven by a motor 34. This equipment together with appropriate lenses is mounted on a carriage indicated by the dotted rectangle 35, which is movable down the face of the cylinder against a return spring (not shown) upon the engagement of a half nut 35 with a worm 31 driven by the shaft 28 through the gears 38, all as is fully described in the aforesaid application. The cylinder 2'! is provided at the upper side with a hinged cover 39 capable of being opened to permit the insertion and removal of transmitting message sheets. In its closed posi- 5 "tion'the cover 39` causes the engagement 'of a pair `"ofA contactsiil, these contacts being arranged.' to open with the-opening of'thecover 39. Pivoted 1 upon 'thecover 39 l-is a latch member 4I adapted, when depressed `by the -ngerA leverd," to close "a contact bank indicated generally at.43, and to bel latched in such depressed position by a forked lever` lili operated by a locking magnet 45. In addition to the apparatus described above, 'the equipment at each station, such as A1, includes an amplierlt connected to the output of `the photocell 32 by the conductors 41,'two signal-lamps 15S and II9` for indicating, :respectively, when a message Yis being recorded at the `station of destination, and when the recording of the message has beencompleted. A relay 50 "fis also providedat each station, asA1, for controlling the operation of the Message Recorded lamp' 49.

The relay control equipment ateachsstation `comprises a polar relay 5I adaptedto control through its marking and spacing contacts a set v cfthree control relays 52, 53 and 54, the functions of which will appear in the detailed description of the operation. A power transformer 55 is also provided at the transmitting station for supv4plying the 'energy for operating -thef'locking magnet 45, the half nut magnet 56, and the relay 5B. `A pair of blocking condensers 5l are inter- .posed between the amplifier .15 and the outgoing Code detector All of the`equipment described in the above paragraph is individual to each jack RJ 1, RJz, etc.

Also at each switchboard position at which incoming lines terminate and outgoing lines originate, and common to all incoming circuits at this position, is a code detector for reading thecode address transmitted from the message blank and for indicating tothe switchboard operator the desired destination of each incoming message. This code responsive device comprisesV a Vacuum tube detector-inverter (i5 for converting the in.. coming code modulated carrier signals into D. C. impulses. The output of the detector is con-fv nected in parallel to two relays 55 and 61. The make contact of relay 55 is connected to the solid ring 63 of a start-stop distributor 69 of conventional form, and the armature of relay 66 is connected to battery. rlhe armature of relay S1 ,is connected to a grounded condenser 10 arranged to be charged through its front contact and to be discharged through its back contact and the winding of a relay 'Il to ground. This latter relay serves, 'when momentarily operatedv from the condenser lli, to operate the distributor start magnet 'l2 and thereby release the distribu- .tor brush arm 'i3 for a single revolution. The `segmented ring I of the distributor'A is divided tinto nine segments numbered I-9, corresponding to the eight indexed positions of the code'zone I3 ofthe message blank and the solid dark portion `vI2, respectively. Each of the segments I-8 is v'connected to one terminal respectivelyofa bank *75* -ofeeight discharge lamps,` the opposite-'elecv trodeslV ofaflwhichf-.arer grounded. nA storagefc'ondenser` 16 bridgedabout each Ilamp's'ervesfztof prolongtheldischarge' therethrough. 1.Thel-lamps 'I5 may be suitablyI arranged in` individualrfcompart- 1 carrying transparent numerals .iptasis well runderstood-l'inf the art. .Thai frame 'llmay-rbe 'loca-ted: above the switchboard: position where'it 'is readily observable-bythe switchboard`=operator. 'iThe .brush armofthe distributor"Y 59 is i driven byianysuitable .motor r ati-the camel speed asi-.fthe

fcorresponding incomingvco'de signal.

@The inputside of the"deteotordnverterlieis .'iconne'ctedi throughr-one.v conductor ef ini fmu'ltiple @-to'zone side 1 of Stheroutputfoil eachot-the lreceiving -amp'liiiersv 53,1 58', 1 etc. Yfheaoth'er: outputrconductor 3@ of the detector-inverter is multipledto "fthe opposite side of-each cil-the armiliers58,' 58', etc. through individual, normal-ly Hopen push vbutton switches SIQSI-, etc.,associatedfwitlreach receiving jack.

` Before proceedingwithl the 'description f? 'the described.

" Letfit `beassulned that the transmitter at sta- `tion A1 is `idle and that there yis noI plug ini the receiving jack RJ I at the central station. Under such conditions Ythere will be Ano potential applied Isc-thermes Ll; L2, will be in its mid-position and the` re1ays52. I53

and the polar relay 5I "(Figifil) 'and'54- will all be'deenergized. Alsoyatstation -A1 there will be no energy lin any parts ofvv the circuit. If now an operator at 'station A1 desires to transmit a facsimile message to a remote station of the system, 'she marks thecode address 'on the message, by making vertical marksopp'o- 'site/"the appropriate indexes, opens the cover 39 @of the transmitting cylinder, andplaces therein the desired message for transmission. The coded zone is so arrangedas to be located opposite the vuppermost or starting position of the scanning carriage 35 so that when the transmitter is startedfthe coded address will be immediately `transmitted to the line.

On the closing of the cover the contacts 40 close butthe circuit' therethrough is open at the back contact of relay 50.

The operator depresses the'hand lever 42, moving lfthe switch 43 to engage all of its lower contacts. -T-his switch at contacts 82 completes a circuit fromterminal A ofthe A. C. power source through the conductor 83, thence in parallel A"through the cylindermotor '23, exciting lamp 3l,

chopper motor 34, and the power supply for the 'amplifier 46,3 to the conductor-Stand thfnce by the contacts-32 and conductor- 85 to the opposite i side B of the power supply. "The Amotor 29 starts "fthe rotation of the cylinder 2v but the scanning y' carriage 35 remains stationary since the half -nutfS is `disengaged from the `worm 31. The

ifilight from the lamp 3l is reflected from :the cylin- YderZTthrough the chopper disc 33 and received by the photocell 32," amplified by the' amplierll and applied to the lines L1, L2. It comprises a "steady tone interrupted by the solid dark area'l2 and the code markings on the blank. At 'the central station this code modulated tone is'retion of relay 59.

Lfterruptions but the relay 63 operated 'thereby is sufficiently slow so that it remains operated-conthe storage condensers 16.

tlnuously to thereby operate the signal lamp 63 thru contacts 64 and apply positive battery to the supply. The relay 53, through its inner armature and front contact, completes a circuit through the winding of relay 52 from the power source, and the relay 52 at its outermost armature closes a circuit from the secondary of the transformer 55 and the conductor 86 to thelocking magnet 45, which operates the locking lever 44 to lock the hand lever 42 depressed, thereby retaining the switch 43 in its lowermost position. Up to this time, ordinarily less than a second, it is necessary for the operator to hold the lever 42 depressed.

It will be recalled that when the relay 6o at the central station operated to apply positive battery to the line L2, that the signal lamp 63 operated to advise the receiving operator of the incoming call. Upon observing this signal, the operator closes the associated switch 8|, thereby connecting the output of the amplifier 53 to the detector 65, which also serves to invert the D. C. signals. Various forms of detector-inverters are well known in the art and, therefore, it is unnecessary to describe such device in detail.

Therefore, relay 66 will be operated whenever the code marks on the message are scanned. Relay 61 is slightly slow to operate, however, and does not respond to the code marks but only to the prolonged pulse from the phasing area I2 of the blank. Therefore, during scanning of this area the condenser 10 is connected to charging battery. As the scanning passes from zone I2 to zone II of the blank, however, relay 61 releases and causes the condenser to discharge through the winding of relay 1I of the distributor 69 which operates momentarily to energize the start magnet 12 and release the brush arm 13 in phase with the coded area of the transmitting blank, resulting in the operation of the selected lamps in the bank 15. These lamps are energized once for every revolution of the transmitting cylinder,

causing the selected lamps either to flicker or glow continuously depending on the capacity of Ordinarily the condensers 16 will be sufficiently large to hold the lamps energized for a full revolution, so that they glow steadily as long as the switch `8l is depressed.

The operator noting the called number may then make the appropriate switching operation.

the corresponding jacks TJ I I, etc. at each switchboard position, as will hereinafter appear. The operator then inserts the opposite end of the patching cord in the receiving jack, as RJI, of the calling transmitter. This latter operation lifts the amplier 58 from the lines L1, Lz causing rclay t5 to release, extinguishing the call lamp 63 and removing positive battery from line Lz. This causes the polar relay 5I at the transmitter to return to its mid-position thereby interrupting the operating circuit for the relay 53. Relay 52 remains locked up, however, through its inner front contact. The release of relay 53 completes a circuit from the secondary of the transformer 55, the left hand tongue and back contact of relay 53, the second tongue and associated contact of relay 52, conductor 81 and the iower contacts 88 of the contact bank 43 to the She may take one of three courses: (l) patch the s incoming call to an idle channel through the called station jack; (2) direct it to a storage medium; or (3) release the push button 8l and permit the transmitter to idle until the switching operation may be completed. It will be remembered that the half nut 36 at the transmitter has not yet been engaged so that the scanning carriageremains stationary during this period. y

Let it be assumed that the code address indicated a local receiver at the central station as the point of destination of the message and further that there is an idle central oflice recorder available. The operator then will insert one terminal of the patching cord into the idle local transmitting jack, as TJ I (Fig. '7). This immediately busies the associated recorder at all of winding of the half nut magnet 5G, whereupon the half nut 36 is engaged with the driving worm 31, causing a scanning operation of the scanning carriage to commence. As the carriage 35 moves downwardly, the coded zone II is first scanned, followed by the body of the message, and finally by the end-of-message signal from the markings i5.

Means is provided at the recorder, as will subsequent-y appear, for transmitting a signal over conductor L2 to stop the transmitter at the end of a message. This means may in turn be controlled by the end-of-message signal I5 or it ma?, be actuated by a predetermined operation of the recorder itself, as will later be described. The control signal consists of the application of negative potential to line L2 causing the polar relay 5I to move to its spacing Contact S. This movement completes an operating circuit for the relay 5d from the power supply A, B. The operation or" relay 54 interrupts the locking circuit of relay but the operating characteristics of relays 52 and 54 are such that relay 54 is operated for a short interval before the release c-f relay 52 and during this interval a circuit is completed from the secondary of the transformer 55, through the left armature of relay 54, the third armature of relay 52, conductor 89, and contact 831 of the contact bank 43 to the operating windof the relay This relay operates and locks up to the power supply A, B through its left hand winding, and the closed cover contacts 40. The operation of relay 5G also completes a circuit from the power line B, the left contact and armature of relay 55 and Message Recorded lamp 49 to the opposite side of the power source. Lamp 49 thereby signals to the transmitting operator that the transmission has been completed. Immediately aiter the operation of relay 58, relay 52 releases thereby interrupting, at the left hand contact, the circuit for the locking magnet 45, whereupon the locking lever 44 releases the latch 4I permitting the switch 43 to return to its upper position.

The return of contact bank 43 to its upper position interrupts, at contact 82, the operating circuit for the motor 29, the lamp 3|, the chopper motor 34 and the amplifier 4S from the power source A, B, thus restoring all the equipment at this station to normal with the exception of the Message Recorded lamp 49 which remains lighted. The operator may now raiscx the cover 39 to remove the recorded message sheet and in so doing opens the contacts 40, thereby opening the locking circuit to the relay 50 and consequentlyinterrupting the circuit to the Message Recorde 1ampj49;` Station ALisnow-completely.- restored-toits inoperativeorfnormal condition;

Transmittz'ngpposition and locali-acordar lt'V will bef-recalled that fthe :transmitter atsta-s* tion- A11 was initiated ib'y fpatc'hing: the .receiving jack RJ I tothe'fflocal "transmitting jack-TJIat` the central pince. The .transmii'fting:'jacksandt the local recorderfare shown-in'Figc'Y'vvhich will now be rrefe'rredto.

Each of the jacks TJ I, TJ2, eta-comprises,int'Y addition tothe ring and `ltip terminals", two sets of contacts -:QIIfandfSI '(desig'natedlitlli? for.'l the -local jacks, 93'12"?! IT' forrthe-trunk'fjacks', zand? 90S,` 9IS lfor the ystorageojacks) adaptedftofbe closed when the patching plug-is insertedf The'r terminals ofthe local jack'` TJ I "at Position 120i the switchboard are multipledv by'conductors 921ivv` to the correspondingterminals of the corresponzbl ing `jack TJ II at Position -2,`etc. One contact off the svvitchv QIEL at eachjack' is1 grounded and the f opposite contact Yis multiple'd'by conductor 93B* tothe corresponding contacts of leach'of the local A` jacks TJ I, TJ I I; etc, and connectedfby facon-y ductor 9411; thrcughthe Windingof the busy relay 95 to battery. Relay 951isthus operated whenever-aplug Iis inserted fin any* one Vofcth'e local jacks'associatcd Withrthe recorder `of Fig. J7." The operation of relay applies ground to the/conductorJ-Slconnecte'd in multiple `to-one'terminal of Aeaclr'orfthe local "jackT busy lamps '-SIL; STL;

etc# at veach-` position, the loppositev Vterminals of which" are connected to battery.`- As'a conse-` quence the'localjackbnsyjamps operate in each'4 positionl whenever a local jackis occupied infamy position:y

The second vpair"` -ofgcontacts -9 IL'fof j ack TJ I prepares I a--circuit` for the Message 'Recorded"- lamp at that `jacklonly'; this circuit being completedV when the full message has been received'i as will later appear:-

With'cthe "j ack ITJI occupied :by the npatching cord the circuit fromthe Vincoming lines'LI;T L2 arev extended through --the v normal jack' ycontacts putfisconnected;tofaisignalinverter IBI having its output connected "across thestylus \.I23and dr-'um-` :I 031of1th'e facsimile recorder:- Afrrelay :TR

tunedfto .the f frequency ofrthe f end-#'of-'m'essagef signal lltransmittedxfrom the fblankllfis con'- nectedfacross fst-hes inverteroutput.: AirA GJ" starting relayR; .Whichresponds ,fto the-carrierv tone.;v is falso; :connected :across ,the output' ofithe. inverter. c This :relay: isl adesigned to'.r be "operated" during the.periodofwtheiong interruptionk caused by the tphasingc'aread 2 eorfthe transmitting..blank?` and. to 'release at'ithe endfof; this :gperiodai The. :recording-.-apparatus, yindicated.twithinrthe dotted zrectangleeR,-;,is -zprcferably:of` the Vform shown" in Patent.-:2,2.5 5;868,-.grantedSeptemben 16;,1941; to cetali.. Briefly, athisrrecorder comprises means forsupportingthe receiving cyl-4 inder-F ISS? ina .horizontal positionf'forrotation througha frictionclutch controlled-by astop arm through-'a phasing rnagliet:adapted toibefoperatf, edcby: a f received -.signal to start thegdru'm into rotation.v inf phase @with :'the transmitting drum;V It :furtherprovidesfforf the Ysupport ofa vplurality of spare:` messagen blank:A bearing.- drums.. with motorfdriven apparatusefor Tahar-gingv drumsat thecompleton of,eaehfrecordingggoperationgq recording is.. effected electrically by -the, stylus.. I02- bearing on-:the drum, andthe-scanning. is... controlledpby a halfnut magnet, a control .mage A net being provided which, When energizedvsimulftaneously'raises thestyl-us from the cylinderand removesthe--half nut magnet from-the. drivingv worm. l

In Fig.y 7 Vthe phasing magnetis indicated at.. III4,. the drum-changingmagnet at f 85 and the.: stylus Aand half nutmagnet at Il. In addition to. these elementsr the recorderis providedyvith. three'contacts ISL land HB9, contact IIII be inge; associated with the drum changing mecha?. nismrtowopen momentarily near the end.of....the.

f-drum ,changing operation; contact It .is are.

rangedto closefwhen there is no drum in recordf1 inggposition, and contact m9 is closed at the end offeach recording operation.

` Associated with the recorder Ais a `drumchangt ing relay. I I, an endoi-message relayJ I Land. afphasing relay I I2, the functioning.. of` which, Willappear in the following description.of,. the.l. operation of the recorder.

Assume, therefore, that the patching ,cord-has,

@just-been placed inturn in the jacks:TJ I .andi

RJ Io The rst operation at jack TJ I, as ,-statedo energized the local jack busylamp `in. all..coY

responding j acl:A positions. The Y latter operation., atjackRJ-I caused the` positive battery at .they

contact =vof -relay 5I] .to -be removed,. starting. the

calling transmitter, as previously described. The. line .II,.L2 is now extendedto the amplierSBL. and-,the address code'is transmitted y'to-it, ample4 fied, inverted. and applied i to the `stylus |02.;

IeIowever,v the .drum ,83 is atrestV at..this time.;

'I'hiefarmature of start relay SR is on-itsback'. contact at the time transmission. starts but swings over to its front contact as soonvas-.scaniningytherdarkarea I2of the recording fblankA This applies ,charging battery to.` the. grounded armature condenseri I3.V However, at the instant the current to relay SR isinterrupted or:` reduced in `value bymovement of the.- dark area I2@ out vof Y the -pathv of the-scanning rbeam,`4 relay lSI?, releasesfdischarging the l-condensereI I 3. through` theI winding of relay I IJ Thiserel-ay locks 11p through its inner make'contact'to fthe left outer bac-fr:v Contact of theY end-:of-messagL relay ...I I I and remainsenergized throughout the remainder 'of' the transmission; irrespective@ ofthe .action ofwrelay SR'.- At its outer vcontact-it appliesI battery Ato `the phasingmagnet' |04 fito energizev the same and thereby cause the release ofth'edrum stop arm, as described inf-the-afore-iv saidPatent 2,255,868.' Thereupon :the 'receiving drum-I IISstart-s tofrotate in phase withV the trans-1 mittingfdrum` and the facsimile vsignals corre-zV spending to bothr the` ceded address `and body :of

th'eomessage arey recorded upon the receiving.

blankeon the `drum H33:

At the completion of the transmission th'eend-. of-message relay I II operates. This may be effected through either one oitWo-agencies, depending/:onwhich voperates rst. Theerecorder is.p1ovided .\vith a .pair of` end-Of-message. col tacts.-l09 which close on the .completion ofapre-r determined scanning movement ofthe reco-rden: as` .fully set vforth in the patent aforesaid. When these contacts close, ground-is applied therefroml byconductor-` I I4 to the e windingl of relay I I I .to operate .-the,same,l this relay then ;11ocking. up;v through -itsinner left hand armature and the outer., make contact -of re` ay 95, the latter of .Which-.remainsv operated as long as the pluggrefel nal transmitted from the blank I Il is also adapted to operate and lock relay I|| through the response of the tuned relay TR tc this signal, by way of conductors I I5 and I I4.

The operation of the relay I I I interrupts, at its outer left armature, the locking circuit for relay I I 2 which thereupon releases and interrupts the circuit to the phasing magnet |04, stopping the transmitting drum |03. At its right hand center armature, relay III applies negative battery to the conductor |90 and hence to the line L2. As explained in connection with the o,.- eration of the transmitter, this negative battery when received on the polar relay 5I (Fig. 4) stops the operation of the transmitter so that no further signals are transmitted over the line.

At the outer right hand armature, relay applies battery to the left hand winding of the drum changing relay IID. Due to the inclusion of the condenser IIB in this circuit, this current is momentary but is sufficient to cause the relay to operate and lock up from ground at its inner armature over a circuit through the right hand winding of the relay, drum changing contact |01 and the outer right hand armature of relay III. Relay H at its third armature applies ground to the half nut and stylus magnet IE6 of the recorder thus lifting the stylus from the surface of the drum and disengaging the half nut magnet from the driving shaft during the drum changing operation. The scanning carriage is restored at this time to its initial or start position. Relay |I|J at its second armature completes a circuit to the drum changing motor which causes the drum changing cycle to occur, whereupon the recorded drum is removed from the machine and a fresh drum applied in recording position. Near the end of this drum changing operation, as appears more fully in the patent referred to, the contacts |01 momentarily. open, thus interrupting the locking circuit to relay I I|! and causing it to release.

Upon the release of relay I|0 a circuit is extended from ground at the inner right hand armature of relay III, outer armature of relay I I0, conductor I I1 and jack contacts 9 IL to the Message Recorded lamp II8L, signaling to the switchboard operator that the transmission has been completed and the recorder, by virtue of the drum changing operation, is in condition to receive another message. She thereupon removes the patching cord from jacks TJ I and RJ I The freeing of jack TJ opens the contacts SOL and 49 IL, extinguishing the Message Recorded lamp ||8L at contact 9 IL and releasing the relay 95 at contact SDL. Relay 95, at its outer armature, unlocks the end-of-message relay I|| thus completely restoring the recorder to normal. At its inner armature, relay 95 extinguishes the local jack busy lamps 91L, 9'|L, etc. at each of the jack positions.

Trunk circuit numbering machine Let it be assumed that the code address of the next call received by the switchboard operator on the indicator 'I5 is for a distant station serviced by an outgoing trunk terminating in the transmitting jack TJ2, TJ I2, etc. These jacks are constructed and multipled together in the same manner as jacks TJ I, TJI I, etc. The operator then plugs the patching cord between the calling jack and the idle trunk jack, such as TJ 2.

The closure of jack contact 90T operates the busy relay 95T (Fig. 8) over the conductor 94T and relay 95T at its outer armature operates the trunk jack busy lamps 91T, 9'|'T, etc. at each position, over the conductor 86T. The inner armature of relay 95T serves to control the application of either positive or negative battery to the conductor TL| of the outgoing trunk circuit TLI, TLZ. The patching of the jacks RJ and TJZ extends the incoming lines LI, L2 to the trunk circuit TLI, TL2 by way of conductors 92T and the ampliiier 98T and starts the calling transmitter for operation thereover, as will subsequently appear.

It is desirable in connection with messages transmitted over these trunks to apply consecutive numbers to the outgoing messages in order that the operator at the receiving end may check to determine whether any messages have been lost in transmission. For this reason it is desirable to insert facsimile signals corresponding to these consecutive numbers, at the central office,

preferably at the head of the message. In Fig. 8 an arrangement is shown whereby such numbers may be automatically incorporated with the facsimile signals being transmitted from the subscribers transmitter. The arrangement is such that the numbers will appear on the message blank in a space corresponding to the dark Zone I2 of the transmitting blank. It is also desirable for some purposes that the code address be transmitted to the station of destination, and therefore the arrangement is such that the trunk line is automatically switched between the numbering machine and the calling transmitter in phase with the scanning of the zones I2 and I3 respectively of the transmitted message blank.

The automatic numbering machine shown in Fig. 8 comprises an elongated cylinder II9 driven by a constantly running motor through a friction clutch |2| controlled by suitable clutch magnet means, as will presently appear. The driven shaft |22 of the numbering machine carries a cam |23 thereon adapted to close a group of three equally spaced contacts |24a, |24b and I2ic, during each revolution for an interval corresponding to the scanning of the area I2 of the blank at the transmitting station. The scanning carriage |25 mcludes the usual light beam, chopper disc, chopper motor and photocell, and is operated by the worm |26 driven by appropriate gears |21 from the shaft I22. The worm |26 is adapted to be engaged by the half nut |28 controlled by the half nut magnet |29.

The consecutive numbers are suitably printed or otherwise recorded on a numbering sheet, a fragment of which is shown in Fig. 10, these numbers being arranged in three rows or columns, a, b and c, and including in addition to the number the usual station and circuit designations. As will appear, the arrangement is such that the drum i9 operates for a suflcient period following each selection of the trunk circuit to transmit a single number. After one column of numbers has been so transmitted, the drum IIB is indexed with respect to the transmitting cylinder so that the numbering proceeds from the second column and finally from the third column.

The indexing of the cylinder I|9 is effected automatically by providing three equally spaced stop arms I tta, |30b and |3|Jc about the periphery of the clutch stop disc |33, as shown diagrammatically in the lower right hand corner of the figure. The stop arm |3061 serves as the index for the rst or a column of numbers, I30b for the second or b column, and I30c for the third or c column. During the transmission of numbers Y from the first column a, the stop arms |3017 and assoir-,i1 om |c 'are :continuouslyaheld -disengaged fromthe 1 clutchdisc -so that the -control `of the disc issolely under the stop army |30a.5 Similarlyduring: the transmission of the V1second for b :column of numbers the clutch'. disc isssolely under the control ofthe stop karm |3||b,=andduringthetrans-- mission of the'thirdcolurnnlof numbers the disc is solely' under the controll ofthe stopzarm..|30c. Eachv of the stop armsf-issprovided. withian--operating magnet |3Ia, |$.|b,r.|3Ic,.respectiyely. The numbering machine transmitter is providedfwith a 'pair of contacts |32 adapted to be closedrbythe. scanning carriage at the completion of the trans-`V mission of vithelast number i of each column.. I-h'ese contactson each closing operate the ste'p-.` ping magnet 134 ofsarotary switch 3|,` shown as having sixv contacts'withl the :diametrically opposite contactsy strapped .togethen and connected respectively to three-relays |a, |35b and |35c.r Battery is' applied to the rotary switch arm;v |36 .so thatione or the .-otherof these srelays remains-operated throughout the entire period -ofv transmission oxonefor-.the other of the columns of. numbers; Assume that. the switch `armi 36 is4 onithe contact controlling-relay:|35a, which cor-r responds-to. the conditionfwhen transmission-of theinumbers isxtaking place from the rstor a column thereof.' Withl relay :|35a operated, bat; teryis appliednthrough the iirst :two 'inner right hand1armatures- .thereof 'to the clutch .magnets |3|b` andi` |3.|c,n1naintaining them continuously energized@ and theirzV corresponding stop arms continuously disengaged from vthe clutch disc |33; At 'the fouter vright hand 4armature of 'relay |35a a;circuit is extended fromfthe clutch magnet I3| a by'fway'of the conductor; |31 Vto the. make contact of 'av-clutch' control relay N133, '.the 10peration=of which fwill" `be; subsequently described. Likewise the relay y|35bappliesrbatterytto the clutch mag+ nets 3 I a and,1|3 Ic and extends' the :Winding of clutch magnet :I3 Ib tothecontact of the clutchV control -relay |384; Similarly relay |35c .when energized 'applies batterytto :the clutchmagnetsr 137m and |3|b and extends... they circuitfrom` clutch Amagnet z I3 Ic. to .the contacts of 'contr'oll relay |38.

The half. nut magnet `|29 is continuously'engagedziwithv the worm 1|2sduring the period vor scanning eachA .colurnn..;cf numbers and is Mre leased by the closing1ofcontact N|32 through a slow-,tofrelease zrelay .,I 39 to permit 'thas-canning head; to.` return to its initial.,l position-v following the scanning of one column and priorto the scan-` ningfof the vvsucceeding column `of numbers.Y Relay |39 operatesfon th'eclosing of theA contacts |32 t and: holds operatedsuiiciently longcto permit the scanning carriage-toreturnsldespite `the fact that thecontacts |32-are openedat the start of this returnmovement. The return movee ment may-also be elected by voperation of the manual key I 40'.-

Power is supplied to the numbering-machine under `the `control ofv afmagnet |4| and manual switch" |4Z.` Withy this magnet energized the driving motor |25, lightv beam and chopper motor are"providediwith powerA frointhe ALCI source |43. Relay ;|4| lat".its.le'ft"hand armature .also controls a circuit over conductor to the Busylamp 91T '(Fig.' 7)" associated ywith each corresponding .trunkjackqso` that these lamps become energized Whenever power is removed from the numbering machine;- as -will hereinafter Tappeari- Y The numberingrnachine- -isiphased jw-ith'respect `to the line switching magnet |50.

`and causing llaylocks up through the backfccntactz'of aflock-i;

izig-` relay |41. Asa consequence Wh'enpthe trunk.; jack is connected toithacalling jackptostartftheY distant transmitter, the signals-.from ther-coded;V area ofV `the blank are amplified .by-.the `amplifiers 98T land, through relay |44, serve to operate th'e clutch control magneti |38 to. close itsfcontacts:x

`This operation occurs; as stated,at the comples.v

tion of the scanning of :the dark area-112 ofthe.t message .-blanlr. The relay |38`at-fits innenright; hand armature completes acircuitr-frombattery@- oventhe conductor |43 '.'to :the leftffront contactsA offrelays .|35a, b'andcgin. parallel, ,andffthence' by conductors 24m, b and c-to-the carn'contactsfV |24a, b and c, in parallel, andbyconductorz|49@ The magnet;l `when energized serves to transfer the trunk circuit TLI, 'IL2 from the calling line to the outa put 'circuit I5| ofthe numbering machine.. Ate` its outer right hand armaturerelay `li'iappliesi. battery over conductor |31 to. one of the clutch magnets IBIa, b or c, depending upon the position of the rotary switch |34, causing-.the drum I IS ito be released for rotation with theparticular column of numbers. then being transmittedmr phase with the dark are-a` I2 of the transmission'A blank.- As stated, the cam contactsl|24arbiand c.; are closed once during each revolution butztheirf effectiveness upon the switching relay .|50 is de-y pendent upon the energization of one of the mag-1 nets I35a, J or c so that the switching relay |50 is actually operated only once during each revolution and, as stated, inphase withthe scanning of the darkareazl of themessageblank. Dur-f ing the time relay |59 isv operated' transmission occurs from the numbering machine vdrumr||9 and,`due to the indexing thereofjonly;fromthe proper column of numbers. The `consecutive numbers are therefore interposed between the successive groups of code impulses. The transmission from the numbering machine continues: until the complete number has been transmitted* This'is effected by allotting tc-each consecutive number on the sheet a distance, lengthwise of the sheet, equal to the'pitch of the worm |26" ie worm to make one-complete revolution for -each number transmitted; For this purpose a canr element |56 on thegear I 21`facts to close momentarily a pair' -oi-'contacts4 |51 during the last revolution of f thedrum`| I9, in veach cycle. Contacts |51, on-wzlos` ing, operate the locking relay |41 to"u1'1l0.ckvreV lay |38 and thus interrupt Y'the circuit previously-v established to the particular stepmagnet |3|a, b` orc, therr in control ofthe ,clutchl |33. The numf '-beringmachine thereupon stops -at^the 'end ro the revolution, with contacts "7| 51 Yfopen;.in1readiness to transmit the next'number. The circuit to the switching magnet 15E is opened atgthe inner rig'htrhanolV contact of -`the magnet i |38 so ,thatl thereafter' transmission over the trunk TL'|,' TL'Z, occurs solely. from the distant OrsubScribers: transmitter.

. Before ,describing Ythe ,distant recordenzand'the. 1 arrangement at the receiving station; itfshbl'lld be noted'thata polarl relay |60"is provided at the switching oice having its winding connected between ground and the trunk conductor TLZ. The marking contact M of this relay is connected through the winding of a relay it! and the spacing contact S is connected through the winding of a relay |62, so that battery applied at the tongue of the relay will operate the relays I6! or |62 depending on the position of the armature. Relay |6| when energized serves to operate the Message Recorded lamp ||8T, of Fig. 7, associated with the jack TJ 2. This circuit extends from the front contact of relay |6| over conductor |63T and jack contacts 8|T to battery at the lamp ||8T. Relay |62 at its inner armature applies ground to the busy lamps 91T, associated with the jacks TJ 2, TJ I2, etc., this circuit being completed over conductor 95T. At its outer armature and front contact relay I62 applies negative battery over the conductor 64 and one of the conductors 92T, which may be traced through to the line L2 extending to the subscribers station. The operation of the polar relay |68 is controlled from the distant recorder and will be described in connection with the operation of the recorder.

Also bridged across the trunk circuit T Li, TLZ is a jack IE5 adapted to receive the plug |66 for connecting a monitoring recorder |62 to the outgoing circuit, if desired.

Remote trunk recorder The recorder at the receiving station at the terminal of the trunk line TLI, TL2 is shown in Fig. 9. It comprises a drum changing facsimile recorder oi the same type as shown in Fig. '7, including the drum E83, associated stylus |82, phasing magnet |85, drum changing magnet |85, stylus and half nut magnet |86, and the drum changing contacts itl, no drum contacts |68, and message-end contacts E89. In addition a number of control relays are provided similar to the relays SR, IIE, ile and lil of the local recorder of Fig. 'l and similarly indicated in Fig. 9. Additional signal control relays M38 and |68 are also provided together with a polar relay H8, the latter of which has its winding connected between ground and the line conductor TLI. The recorder of Fig. 9 is adapted to be connected to the trunk circuit TLi, TLZ through a. jack and plug I'II, a receiving ampliner 98T and an inverter HlIT.

When transmission is started over the trunk line TLI, TLB, the 4first signals consist of the coded address transmitted from the Zone of the message blank. The relay SR in response to the dark area of this coded zone operates to its front Contact so as to charge the condenser |12` connected between its armature and ground, and upon interruption of current at the end of the dark area of the coded zone this relay releases and discharges condenser |12 through the relay ||2 in the same manner as described in connection withFig. 7, thus operating the phasing magnet |254. The recorder thereupon starts to operate and records the number transmitted from the numbering machine at the central cnice with the coded address interspersed therewith, then the body of the message and the end-ofmessage signal. At the completion of transmission the relay I is operated either by the tuned magnet TR in response to the received end-ofmessage signal or through the closing of the end-of-message contacts |69, whichever occurs rst. Relay locks up through the inner left hand make contact to the spacing contact of polar relay |10. This relay is held on this con tact at this time by the negative battery transmitted over the trunk conductor TLI from the make contact and inner armature of the relay T associated with the jack TJ 2 (Fig. 8). Relay lli at its outer left hand armature unlocks the relay 2 in the same manner as at the local transmitter described in Fig. 'l and at its outer right hand contact energizes the drum chang- 'ing relay III) which effects the drum changing operation in the manner previously described. At its middle right hand armature relay I I applies negative battery through the back contact of relay |68 and conductor |'I3 to the conductor TL2 of the trunk circuit. At the switching ofce this operates the polar relay |60 (Fig. 8) to its spacing side, which energizes relay 62 and this in turn, as stated, applies negative battery through its outer armature to the line L2 to the subscribers transmitter, bringing this transmitter to rest and discontinuing the transmission therefrom. At its inner right hand armature relay (Fig. 9) applies ground through the back contact and outer right hand armature of relay I I0 to the winding of relay |68. This relay does not operate, however, until the drum changing operation has been completed at which time the relay ||0 falls back and operates relay |68. Relay |68 is suiiciently slow, however, so that it was not operated between the time relay rst operated and the resulting operation of relay Ile. The operation of relay |68 applies positive battery through the conductor |13 to the trunk conductor TL2 to operate the polar relay |60 (Fig. 8) ot its marking side, thus deenergizing relay |62 and operating relay ISI. The release of relay |62 removes the negative battery from the line L2 and the operation of relay |6| applies positive battery to the conductor |63T leading to the Message Recorded lamp at the switchboard. The operator at the switchboard, noting that transmission has been completed, may pull down the patching cord. When the plug is removed from the jack TJZ, relay 95T releases, disconnecting the ground at its outer armature from the busy lamps SlT at each cor-V responding jack and applying positive battery at the back contact and inner armature thereof to the line TLI. At the recording station this positive battery operates polar relay |18 to its marking contact and thus applies ground through the winding of magnet |69 to the contacts |88. Should these contacts be closed due to the absence of a recording drum, indicating that the recorder is not in condition to receive, relay |69 operates and again applies negative battery to the trunk line conductor TLZ to again operate relay |60 to its spacing contact and thus to operate relay |62. At its inner armature relay |62 applies ground to the busy signal 91T associated with each of the jacks. The negative battery at the outer tongue of relay |52 is not applied to the line conductor L2 at this time, however, since the jack TJ 2 is unoccupied. As soon as a new supply of message cylinders is provided at the recorder, the no-drum contacts |88 open toremove negative battery from the conductor TL2 thereby to release relay |62 and remove the busy signal at the various jack positions.

Storage mechanism y If, when an incoming call is registered on the indicator 15, there is no idle circuit available for the message to .be transmitted, the switchboard operator may divert it to a storage medium and 17 retransmit it when a channel becomes available. If desired, one unit of the selecting code, for instance, the eighth, may be used to indicate the preferred or deferred nature of the message so that when the trailic is heavy, deferred messages may be stored at the central cnice for transmission during periods of lighter loads, thus conserving the trunk circuits for preferred messages.

In Fig. 11 we have shown a magnetic wire or tape type of signal storage suitable for the above purpose. The storage jacks TJ4, TJ E4, etc. (Fig. 7) are multipled at the various jack positions in the same manner as the local and trunk line jacks, and provided with similar "Busy and Message Recorded lamps. The Busy lamps 97s, Qls, etc. at each position are operated from the contacts of the busy relay 95s (Fig. 11) over conductor 95s, relay 95s being operated from the jack contacts 90s over conductor Q43 and jack contacts 90s, in the same manner as described with reference to the local and trunk line jacks. The Message Recorded lamp ||8s of the occupied jack is energized through the contacts 9|s of its associated jack under the control of the storage mechanism, as will later appear. Jacks TJ il, TJ i4, etc. extend the incoming circuit, such as LI, L2, by means of the patching cord, to the input of the amplifier 08s (Fig. ll) and thence to the recording magnet |80 of the storage device.

The storage means includes an endless magnetic storage medium, which may be in the form of a tape |8| either of steel or of other flexible material coated with a layer of iron particles capable of being selectively magnetized by the applied signals. The tape |8| passes from the recording position at magnet |80, between a drive roller |02 and associated pressure roller |83, and thence into an accumulator or storage receptacle |84. The accumulator may be similar to that used in the storage of perforated telegraph code tape, as shown in Patent No. 2,259,517, to Drenkard. Briefly, it consists of a box having its front and back walls spaced apart a distance kslightly greater than the width of the tape. An

drive roller |85 the tape passes around any suit able arrangement of idler rollers, such as roller |9| to a third drive roller |92, from which it is passed into a second accumulator 93 and thence through the single message storage section |94 and past the erasing magnet |95.

'The receiving drive roller |82 is driven from a continuously operating motor |96, through a friction clutch |9l controlled by a stop arm |98 and associated clutch magnet |09. The transmitting drive roller |85 is driven by a motor 200 through the friction clutch 20| controlled by the stop arm 292 and clutch magnet 203. Drive roller |92 may be conveniently geared to roller |85. The drive rollers may take the form of toothed Wheels engaging in perforations in the tape as is well known in the art.

Disposed across the inlet of the accumulators |84 and |03 are the tape levers 204 and 205, re-

Il-f) 18 spectively, the arrangement being such that when the tape supply in either of the accumulators is exhausted, the tape lever will be raised to open the contact 206 associated with lever 204 and to close the contact 20'? associated with lever 205.

The purpose of lever 205 is to control 4the Busy lamp associated with the storage jacks so that it will indicate a busy condition when there insuilicient available tape ahead of the recording magnet |30 to record a complete message. With no tape in the accumulator |93 and contacts 2li? closed, ground will be applied by the wire 208, to the busy conductor 96s, energizing the busy lamp ills at each jack position.

The lever 204, through its contacts 206, controls a Message Waiting lamp 209 associated with the transmitting plug 2|0 of the storage device. Plug 2|il is connected by conductors 2|| to the terminals of the transmitting magnet |90. As long as any tape is available in the accumulator the contacts 206 will be closed and lamp 209 lighted, indicating the presence of a completely stored message available for retransmission.

The plug 2|0 is weighted and serves when seated, as shown, to hold open the spring urged contacts 2|2 so that whenever the plug is lifted to make a connection, as to one of the outgoing trunk jacks TJ2, etc., a relay 2|3 will be operated. This relay at. its left armature completes a circuit from battery over conductor 2|4 and the outer right armature and back contact of relay 2 i5 to the clutch magnet 203.

A push button switch 2|6 is also provided adjacent the plug position and serves when depressed to complete at its lower contacts the above clutch magnet circuit, and at its two upper sets of contacts, to connect the retransmitting circuit 2|| to the input of the amplifier 2||, the output of which is connected by conductors 2|8 to the input of the detector 65 (Fig. 5) of the code detecting apparatus.

The Vclutch magnet l at the recording side of the storage medium is operated from battery at the inner armature and make contact of relay 95s, conductor 2|9, and the outer armature and back contact of a relay 220. Relay 95s, it will be remembered, was operated by the occupation of jack TJ4 by the plug of the patching cord, so that `the plugging-up operation automatically starts the recording operation. The function of the remaining relays and circuits associated with the storage device will become clear from the following description of the operation of the storage means.

Assume that the operator has just patched her cord between the incoming lines Ll, L2 and the storage jack TJ4. The insertion of the plug in the incoming jack RJ removes positive battery from line L2, as before described, and causes the scanning of the transmitting drum at the subscribers station to start, thereby transmitting the'svvitching code followed by the body of the message, and completed by the end-ofmessage frequency.

The occupation of the plug in the jack TJ4 operates relay 95s, as described, lighting the busy lamp lls at all corresponding jack positions and energizing the clutch magnet |99 of the storage recorder. The signals received over line Ll, L2 are amplified at 90s and applied to the recording magnet and recorded as magnetic variations in the tape |3|. This recording continues until the end-of-message frequency is received.

A tuned relay 22|, responsive to this frequency only, is connected across the output of amplifier 98s .and upon reception of the end-of-message signal operates a slow-to-release relay 222. Relay 222 picks up and charges its armature condenser 223 during the period o f transmission of the end-of-message signal. When the transmission of this signal is completed, relay 222 again releases, discharging thewcondenser 223 through the winding of relay 22S. Relay 22@ operates and locks up through its inner right hand armature, conductor 22A and middle armature of relay 25s, to battery. At its outer right hand armature, relay 222 interrupts the energizing circuit to the clutch magnet 99 causing the stop arm 93 to release and stop the ribbon feed. However, by virtue of the slow-to-release characteristic of relay 222 a short interval of blank tape is advanced past the recording position following the termination of the end-ofmessage signal, thus separating the received message slightly from the succeeding message.

Relay 22e at its left hand inner armature applies battery to the conductor 523s to `energize the Message Recorded lamp H88, thereby signaling the operator that the connection may be broken down. At the same negative battery is applied from the left hand outer armature of relay22) to the conductor 224 and thence to the line L2 extending to the subscribers station. As heretofore described, this negative battery stops the operation of the distant transmitter.

When the operator removes the plug from the jack T54, relay 95s is deenergized, interrupting the locking circuit to magnet 229 and also extinguishing the busy lamp at each jack position.

A manual switch 225 is provided to advance blank` tape past the recording position, when desired, in order to permit the last recorded rnessage to be moved into retransmitting position.

In retransmitting a message from the storage tape, the operator, noting the Message Waiting lamp, momentarily depresses the switch 2 I6 and reads the code address of the stored message on the indicator 15. She then lifts the plug 2l@ and plugs it into the appropriate outgoing jack, for instance, trunk jack TJ 2. The lifting of the jack permits contacts 2l2 to close, operating magnet 2I3 and through its left hand armature, operating the transmitting clutch magnet 223 to release the clutch 25H and start the advancement of tape past the transmitting magnet ISB. The stored signals are thus transmitted over conductors 2l l, the plug 2HE, jack TJ2 and out over the trunk TLI, TLZ. The message numbers are automatically inserted by the numbering machine associated with the selected trunk and the complete message with number and code address is recorded at the distant station.

A tuned relay 22S, responsive only to the endof-message frequency, is connected across the output of the retransmitting magnet IQi and serves to operate relay 221 during the transmission of the end-of-message signal. At the coinpletion of the end-of-message signal relay 221 releases to operate magnet 2I5, in the manner described in connection with relay 223, to thereby interrupt at its outer right hand armature the circuit to the clutch magnet 253 and stop the advancement of the tape. Relay 2|5 locks up at its left armature, conductor 22S and the right armature and contact of relay 2l3 until the operator restores the plug 2li? to its seat. Relay 2I5 at its inner right hand armature completes 20 a circuit from battery, over conductor 2,29 to'th Message Completed lamp 233 at the switch# board position, indicating to the operator that the connection may be broken down. K

It will be understood, of course, that in place' of terminating the output conductors 2 Il of the @transmitting-magnets in plugs 2li), they could equally well have been terminated in jacks, such as RJ 3, at the switchboard, and the connections to the outgoing circuit made by patching cords.

Plural switching' In Figs. l2 and lthere is shown a modication of the invention which permits the switching connection to be completed from the facsimile transmitter, through va plurality of switching oices, to the recorder at the station of destination of the message. This is facilitated by that aspect of the invention which permits the code address to be transmitted continuously during the entire period of setting up of the switching connections irrespective ofthe time involved.

In this modification the facsimile transmitter indicated by the box diagram 211.0 is identical with the apparatus and circuits shown in Fig. 4 and is connected by the lines LI, L2 tothe jack RJ! at the nist-switching station. The call and indicating mechanism 24| at this station is identical to the call and indicator equipment shown in Fig. 5 with the exception that an additional contact 242 has been added to the relay 60 to control the operation of a magnet 243 for operating a signal lamp 244, the purpose of which will appear hereinafter. At the switching station the transmitting jacks TJI, TJ 2, TJ4 are constructed and multipled to other switching positions in the ofce in the same manner as shown in Fig. 7, and the apparatus and circuits for both the local recorder 245 and the storage device 46v are `identical Vwith the local recorder of Fig. 7 Vand the storageequipment of Fig. 11. The control Yrelays associated with the trunk jack TJ,2,how ever, are somewhat different from those shown in the Ytrunk jack circuit of Fig. 8, and the functioningy of these control relaysand circuits will be, bestunderstood by describing the operation Athereof in connection with a switching connection'. Thus, when 4a call is initiated from the facsimile transmitter 2,42, the signal light (i3 operatesas heretofore described, and the switching operator actuatesthe key 8l tov cause the code address to be shownon the indicator 11'. If Vthe ,code address indicates a local recorder or a called station which is busy, the patching cord' ZEis plugged either into the, local jack TJI or the storage jack TJ4, and the .operation proceeds in exactly the same manner heretofore described. However, if the messageis destined for an idle station-serviced by the trunk jack TJ 2 over the trunk line TL, TLS, the operator` patches the cord between kthe jacks RJI `and TJ 2. The sequence of operationis to insert the plug of the patchingcord first into jack TJ2 and immediately thereafter into the jack RJ l. The insertion Vof the plug into TJ2 operates the jaol: contacts 35T and 91T in the manner previously described, and the closing of contacts 92T operates the relay 95' as heretofore explained, thereby to energize the busy lamp 92T at its left hand armature. At its outer right hand armature relay 95 applies positive battery through the back contact cfa relay 241 to the tip contact of the jack TJ2 from which it is extended through the patching cord to the line L2 as soon as the patching connection has been completed at jack RJ l. This positive battery replaces the positive batteryI 21"' previously applied from the middle armature of the relay 60 and which is removed at the time the patching cord is plugged into the jack RJI through the interruption of the signaling circuit to the amplifier 58. In view of this continuous application of positive battery to the line L2, the facsimile transmitter continues to rotate idly and to transmit successively the code address. This code address is extended over the trunk TL5, TLS to the second switching station C. The terminating jack RJ at this station is provided with call and indicator equipment 248 identical with that at station B and the extended code address signals operate the relay 65 at this station to apply positive battery through the middle contact of this relay to the trunk circuit TL()l and also at its inner right contact to cause the call lamp 63 to become energized. The positive battery applied to TLG operates a polar relay 250 at station B to .its marking contact causing the operation of relay 241, this latter relay locking up through its right hand winding to the inner right armature of relay 95. Relay 241 removes the positive battery applied through its left hand contact from the line L2 but this positive battery is replaced by the positive battery at the tongue of the polar relay 255. Thus any further application of positive battery to the line L2 is controlled solely by the relay 255.

The operator at station C in response to the lighting of lamp 63 depresses the indicator key 8|, reads the code address on the indicator 1l, and extends the circuit through the patching cord 26 to the next section of the connection. This may be a trunk circuit TLI, TLB (Fig. 13) identical with TL and TLS and equipped with identical control apparatus and circuits. However, for the present purpose let it be assumed that the message is destined for a local recorder at station C, such asis serviced by the jack TJ I at this station. The operator then inserts the patching cord into the jack TJ I and thereafter into the jack RJ. The facsimile recorder associated with the jack TJI, included within the dotted rectangle is identical with that previously described, but the control circuits for this recorder are somewhat different than heretofore referred to. When the plug is inserted in the jack TJ I, the jack contacts GOL, 9 IL are operated, the former of which operates the relay 95L to operate the busy lamp 92L through its left armature in the usual manner. There is no battery, however, applied to the tip of the local jack at this time and since positive battery was removed from the line TLG by interruption of the circuit to amplifier 58 upon the insertion of the plug in the jack RJ, this patching operation serves to reits inner right hand armature, the push button switch 252 and the outer right hand armature of relay 55L. At its middle left hand armature relay III interrupts thev locking circuit for the thereby shunting out this relay from control of the relay |55. This prevents further response of relay I I2 and restarting of the recorder as long as relay III remains locked up. The positive battery supplied through the right hand armature of relay I I I', in addition to operating relay` IIE to initiate the drum changing operation as heretofore described, is extended through the upper left hand contacts of push button switch 252' to the tip of the jack and thence through the patching cord to the line TLS, again operating the polar relay 255 at station B to its marking contact and reapplying positive battery over the line L2 extending to the transmitter.

Referring to Fig. 4, this positive battery operates the polar relay 5I at station A to its marking side rta-energizing relay 53 and thus opening at the outer armature of this relay the circuit from the secondary of 'the transformer 55 to the half nut magnet 55 whereupon this magnet withdraws the half nut 36 from the worm 3l causing the scanning carriage to return to its uppermost position. The drum 2'I, however, continues to rotate so that the code address is again transmitted over the circuit. It is ineffective at the recorder, however, to release the phasing magnet due to the shunting arrangement of the phasing re.ay II2 as previously described.

The operator at the recording station is now free to inspect the message received and either to eiiect a repetition of this message or to release: the circuit as desired. Should it be desired toI obtain a second -copy of the message, the push button 252 is depressed momentarily to unlock the magnet III whereupon the short-circuiting groundl of relay II2.-is removed and this relay again responds to the phasing pulse being transmitted from the code address portion of the message blank. This releases the phasing magnet |54 again and the entire recording cycle is ren peated..

move all battery from the trunk conductor TLG.

At station B this causes the polar relay 25E) to move to its mid-position thereby removing positive battery from the tip of the jack TJ2 and through the patching cord from the line L2 whereupon the scanning operation of the transmitter is started as previously described. The code address is rst transmitted and acts as previ-- ously described through the relays |55 and ||2 to release the phasing magnet |04 to start operation of the recorder. The message is thus received upon the recorder in the same manner as it is received upon the local recorder in Fig. 7, and at the end of this operation the message-end contacts |59 close to operate the end-of-message relay III. Relay III' at its outer right hand armature operates the drum changing relay III) which functions as in Fig. 7 to complete a drum changing operation. Relay III locks up through Magnet 25d locks up through its right hand orholding winding to the inner right armature of the relay and prepares a circuit from the back contact of relay 253, outer armature and make Contact of relay 254, conductor 255, jack contacts 9 IT to the message recorded lamp I I8T. This lamp, however, does not operate at this time. At its middle armature relay 254 applies negative battery to the tip of the jack TJ 2 and thence through the patching cord to the line L2. At the facsimile transmitter of Fig. 4 this negative battery serves to operate the locking magnet 45 as heretofore described to interrupt the operation of the transmitter.

The push button switch 252' at station C is latched in its depressed position by a latch methv 

